Dose setting mechanism for priming a drug delivery device

ABSTRACT

A method and system for providing a drug delivery device. The drug delivery device comprises a dose setting mechanism comprising a spindle and a cartridge holder coupled to the dose setting mechanism. The cartridge holder comprising a cartridge having a movable bung at one end of the cartridge. The cartridge holder must be rotated before a dose may set with the dose setting mechanism.

BACKGROUND

1. Field of the Present Patent Application

The present patent application is generally directed to drug deliverydevices. More particularly, the present patent application is generallydirected to drug delivery devices, such as pen type drug deliverydevices. Such devices provide for self administration of medicinalproduct from a multi-dose cartridge and permit a user to set thedelivery dose. The present application may find application in bothresettable (i.e., reusable) and non-resettable (i.e., non-reusable) typedrug delivery devices. However, aspects of the invention may be equallyapplicable in other scenarios as well.

2. Background

Pen type drug delivery devices have application where regular injectionby persons without formal medical training occurs. This is increasinglycommon among patients having diabetes where self-treatment enables suchpatients to conduct effective management of their disease.

In certain types of medication delivery devices, such as pen typedevices, cartridges of medication are used. These cartridges are housedin a cartridge holder or cartridge housing. Such cartridges include abung or stopper at one end. At the other end of the cartridge, thecartridge may comprise a pierceable seal. To dispense a dose ofmedication from such a cartridge, the medication delivery device has adose setting mechanism that uses a spindle to move in a distal directiontowards the cartridge and to press a distal end of the spindle againstthe bung. This expels a certain set or preselected dose of medicationfrom the cartridge. In order to insure dose accuracy, it is importantthat the distal end of the spindle remains on the bung of the cartridgebefore, during and after injection of a dose of medicament.

One perceived disadvantage of certain known medication delivery devicesis that because of the various tolerance differences that may occurduring manufacturing (e.g., tolerance differences that may arise duringcomponent molding) of the various parts making up the drug deliverydevice and the desire to not pre-load the bung axially in the assembleddevice, there may be a gap between the end of the spindle and thecartridge bung after the medication delivery device has been assembled.In other words, when initially assembled, the cartridge (and hencecartridge bung) may not be in contact with the distal end of thespindle. Therefore, if a user using the drug delivery device for thefirst time dials a dose, the actual dose received may be equal to thedialed dose less the initial gap between the distal end of the spindleand cartridge bung. The air gap between the cartridge bung and distalend of the spindle may be equivalent to a dose that causes the receiveddose that is outside preferred dose accuracy limits. For example, thisair gap may be equivalent to the loss of between 0 and 10 units (i.e.,0-0.14 milliliters) of drug product on the first dose.

There is, therefore, a general need to take these perceived issues intoconsideration when designing either resettable or non-resettable drugdelivery devices, such as pen type drug delivery devices.

SUMMARY

According to an exemplary arrangement, a drug delivery device comprisesa dose setting mechanism comprising a spindle. A cartridge holder iscoupled to the dose setting mechanism. The cartridge holder comprises acartridge having a movable bung at one end of the cartridge. Thecartridge holder is rotated before a dose may set with the dose settingmechanism.

According to another arrangement, a priming mechanism for a drugdelivery device comprises a dose setting mechanism. The dose settingmechanism comprises a spindle and a dose dial sleeve. A cartridge holdercomprises a cartridge comprising a movable bung and a pierceable seal. Acoupling part connects the cartridge holder to the dose dial sleeve. Aspindle nut, rotationally coupled to the coupling part, couples thecartridge holder to the spindle. When the cartridge holder is rotatedwith respect to the dose setting mechanism, the spindle nut is rotatedand the coupling part moves the spindle into an abutting engagement withthe bung.

These as well as other advantages of various aspects of the presentinvention will become apparent to those of ordinary skill in the art byreading the following detailed description, with appropriate referenceto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are described herein with reference to thedrawings, in which:

FIG. 1 illustrates an arrangement of a drug delivery device inaccordance with the one aspect of the present invention;

FIG. 2 illustrates the drug delivery device of FIG. 1 with a cap removedand with a dose having been selected;

FIG. 3 illustrates a close up view of a drug delivery device before apriming step, such as the drug delivery device illustrated in FIG. 1;

FIG. 4 illustrates a close up view of the drug delivery deviceillustrated in FIG. 3 after completion of a priming step;

FIG. 5 illustrates a close up view of a connection between a dosesetting mechanism and cartridge housing of a drug delivery device in anon-priming state, such as drug delivery device illustrated in FIGS. 3and 4;

FIG. 6 illustrates a close up view of the connection between the dosesetting mechanism and the cartridge illustrated in FIG. 5, in a primingstate;

FIG. 7 illustrates a close up view of a proximal end of the cartridgehousing illustrated in FIGS. 5 and 6, including a coupling part

FIG. 8 illustrates how the coupling part illustrated in FIG. 7 may beused to engage a dose dial sleeve of a dose setting mechanism, such asthe dose setting mechanism illustrated in FIGS. 5 and 6;

FIG. 9 illustrates the coupling part illustrated in FIG. 8 in anon-primed state;

FIG. 10 illustrates the coupling part illustrated in FIG. 9 in a primedstate;

FIG. 11 illustrates a close up view of the stop faces provided along thedistal end of the dose dial sleeve illustrated in FIG. 10

FIG. 12 illustrates a spindle nut that may be used to couple thecoupling part to a dose setting member and to a cartridge housing; and

FIG. 13 illustrates the spindle nut coupled to the coupling part anddose dial sleeve of a dose setting mechanism.

DETAILED DESCRIPTION

Referring to FIG. 1, there is shown a drug delivery device 1 inaccordance with an exemplary arrangement. The drug delivery device 1comprises a housing having a first cartridge retaining part 2, and adose setting mechanism 4. The drug delivery device may be a resettabledrug delivery device (i.e., a reusable device) or alternatively anon-resettable drug delivery device (i.e., a non-reusable device). Afirst end of the cartridge retaining part 2 and a second end of the dosesetting mechanism 4 are secured together by connecting features. Fornon-resettable devices, these connecting features would be permanent andnon-reversible. For resettable devices, these connecting features wouldbe releasable.

In this illustrated arrangement, the cartridge housing 2 is securedwithin the second end of the dose setting mechanism 4. A removable cap 3is releasably retained over a second end or distal end of a cartridgeretaining part or cartridge housing. The dose setting mechanism 4comprises a dose dial grip 12 and a window or lens 14. A dose scalearrangement 16 is viewable through the window or lens 14. To set a doseof medication contained within the drug delivery device 1, a userrotates the dose dial grip 12 such that a dialed dose will becomeviewable in the window or lens 14 by way of the dose scale arrangement16.

FIG. 2 illustrates the medical delivery device 1 of FIG. 1 with thecover 3 removed from a distal end 19 of the medical delivery device 1.This removal exposes the cartridge housing 6. As illustrated, acartridge 25 from which a number of doses of a medicinal product may bedispensed, is provided in the cartridge housing 6.

Preferably, the cartridge 25 contains a type of medicament that can beadministered relatively often, such as once or more times a day. Onesuch medicament is either long acting or short acting insulin or aninsulin analog. The cartridge 25 comprises a bung or stopper (notillustrated in FIG. 2) that is retained near a second end or a proximalend 33 of the cartridge 25. The medical delivery device also comprises adriver having a spindle (not illustrated in FIG. 2). As discussed above,before the device is primed, there may or may not be a gap between theend of the spindle and the cartridge bung.

The cartridge housing 6 has a distal end 23 and a proximal end 27.Preferably, the cartridge distal end 23 of the cartridge housing 6comprises a groove 8 for attaching a removable needle assembly. However,other needle assembly connection mechanisms could also be used. If thedrug delivery device 1 comprises a resettable device, the cartridgeproximal end 27 is removably connected to the dose setting mechanism 4.In one preferred embodiment, cartridge housing proximal end 27 isremovably connected to the dose setting mechanism 4 via a bayonetconnection.

However, as those of ordinary skill in the art will recognize, othertypes of removable connection methods such as threads, partial threads,ramps and detents, snap locks, snap fits, and luer locks may also beused.

As previously mentioned, the dose setting mechanism 4 of the drugdelivery device illustrated in FIG. 2 may be utilized as a reusable drugdelivery device. (i.e., a drug delivery device that can be reset) Wherethe drug delivery device 1 comprises a reusable drug delivery device,the cartridge 25 is removable from the cartridge housing 6. Thecartridge 25 may be removed from the device 1 without destroying thedevice 1 by merely having the user disconnect the dose setting mechanism4 from the cartridge housing 6.

In use, once the cap 3 is removed, a user can attach a suitable needleassembly to the groove 8 provided at the distal end 23 of the cartridgehousing 6. Such needle assembly may be, for example, screwed onto adistal end 23 of the housing 6 or alternatively may be snapped onto thisdistal end 23. After use, the replaceable cap 3 may be used to re-coverthe cartridge housing 6. Preferably, the outer dimensions of thereplaceable cap 3 are similar or identical to the outer dimensions ofthe dose setting mechanism 4 so as to provide an impression of a unitarywhole when the replaceable cap 3 is in position covering the cartridgehousing 6 when the device is not in use.

In accordance with an exemplary arrangement, it may be beneficial toforce a user to prime the drug delivery device of FIGS. 1 and 2 beforethe user dials and injects the first dose. In order to achieve thisforced priming, as will be discussed in greater detail below, the drugdelivery device 1 preferably forces a user to prime the device beforethey are permitted to select the first dose.

The process of forcing a user to prime the cartridge before they canselect and dispense the first dose reduces a potential risk of injectingthe prime dose. The idea of forced priming is particularly advantageousfor disposable devices where there is oftentimes a gap between a distalend of the spindle and the cartridge bung before the device is used.This gap is a consequence of the tolerances associated with theassembled parts as well as the desire not to pre-load the bung axiallyin the assembled device.

If the device is designed so that this gap between a distal end of thespindle and the bung is removed (i.e., the device primed) before theuser is able to dial a dose, then this is advantageous. In one preferredarrangement, the drug delivery device achieves this by the user rotatingthe cartridge holder relative to the housing in order to both prime thedevice and also to unlock the number sleeve so the user can subsequentlyrotate the dose dial sleeve to set the first dose. Preferably, once thedevice has been primed, the cartridge holder is locked rotationally andtherefore cannot be rotated with respect to the dose setting mechanism.

FIG. 3 illustrates a close up view of a drug delivery device 50 before apriming step, such as the drug delivery device 1 illustrated in FIG. 1.FIG. 4 illustrates a close up view of the drug delivery device 50illustrated in FIG. 3 after completion of a priming step. Asillustrated, the drug delivery device 50 comprises a dose settingmechanism 52 coupled to a cartridge housing 54. Where the drug deliverydevice 50 comprises a re-settable drug delivery device, this couplingmechanism comprises a releasable coupling mechanism (i.e., a thread, abayonet lock, a luer lock, a snap fit or snap lock, etc.) Where the drugdelivery device 50 comprises a non-resettable drug delivery device(i.e., a disposable drug delivery device), this coupling this couplingmechanism comprises a non-reversible coupling mechanism.

In this preferred arrangement of drug deliver device 50, the dosesetting mechanism 52 comprises various markings and indications along anouter surface 53. As can be seen in this arrangement, this markingcomprises a marking indicating a locked position (i.e., un-primed state)58 and a marking indicating an unlocked position (i.e., primed state)62. In addition, various intermediate markings 59 are provided betweenthe locked and unlocked position markings 58, 62, respectively.

In addition, the cartridge housing 54 comprises markings along its outersurface 63 and these markings include a positional indicator (i.e., anarrow) 56 that is used to indicate the relative position of thecartridge housing 54 with respect to the outer surface 53 of the dosesetting mechanism 52. In this preferred arrangement, to prime the drugdelivery device 50, the cartridge housing 54 is rotated in direction ofarrow 60. Preferably, the cartridge housing 54 is rotated in thedirection of arrow 60 with respect to the dose setting mechanism 52 sothat the arrow 56 moves from the locked marking 58 and then aligns withthe unlocked designation 62, as shown in FIG. 4. In this final position,the drug delivery device 50 now resides in a primed state. That is, thespindle contained in the dose setting mechanism 52 now resides adjacentor abuts the bung provided in the cartridge of the cartridge housing 54.In addition, in a preferred arrangement, the drug delivery device 50 isalso now unlocked so that the dose setting mechanism 52 may now be usedto set a dose (as illustrated in FIG. 2). Most preferably, in this finalposition, the cartridge holder 54 is also rotationally locked and cantherefore no longer be rotated with respect to the dose settingmechanism 52. FIG. 5 illustrates a close up view of a connection betweena dose setting mechanism and cartridge housing of a drug delivery device70, such as drug delivery device 50 illustrated in FIGS. 3 and 4. InFIG. 5, the drug delivery device 70 is in a pre-primed state. Therefore,with the drug delivery device illustrated in FIG. 5, a user could notset a dose until the device is primed. As illustrated, the dose settingmechanism 74 is rotationally coupled to the cartridge housing 72. Inthis arrangement, the cartridge housing 72 comprises a rib 76 thatengages with an internally formed cavity on an inner surface of the dosesetting mechanism 74. This configuration allows for relative rotationalmovement only between the dose setting mechanism 74 and the cartridgehousing 76 and no axial movement. This rotational relative movementoccurs when the cartridge holder 72 is rotated from the locked position(i.e., FIG. 5) to the unlocked position (i.e., FIG. 6).

FIG. 7 illustrates a close up view of a proximal end 68 of the cartridgehousing 72 illustrated in FIGS. 5 and 6. FIG. 7 also illustrates acoupling part 80 that may be used to couple the cartridge housing 72 toa dose setting mechanism, such as the dose setting mechanism 74illustrated in FIGS. 5 and 6. In this preferred arrangement, thiscartridge housing 72 comprises an L shaped cavity 73 provided along afirst outer surface 75 of the cartridge housing 72. As described withrespect to FIGS. 5 and 6 and as will be described in greater detailbelow, this cavity 73 is used to engage a portion of a coupling part soas to allow relative rotation between the cartridge holder 72 and thedose setting mechanism.

In this preferred arrangement, coupling part 80 comprises a thin metalpressing. However, those of ordinary skill will recognize thatalternative coupling part arrangements may also be used. In thispreferred arrangement, the coupling part 80 comprises a first set ofaxial projecting members 82 a, 82 b that project in an axial directiontowards the distal end 69 of the cartridge housing 72. These projectingmembers 82 a, 82 b rotationally affix or engage a first portion 75 ofthe cavity 73. In addition, the coupling part 80 rotationally couples toa spindle nut and therefore a spindle of a dose setting mechanism andalso acts upon a dose dial sleeve of the dose setting mechanism.

The coupling part 80 further comprises a second set of axial projectingmembers 86 a, 86 b. This second set of projecting members 86 a, 86 bextend in a proximal direction away from the proximal end 68 of thecartridge housing 72. This second set of projecting members 86 a, 86 bengage a portion of the dose setting mechanism, specifically an innerhousing of the dose setting mechanism. As described below, the couplingpart 80 further comprises two inwardly extending arms 84 a, 84 b thatengage a spindle nut of the dose setting mechanism.

FIG. 8 illustrates how the coupling part 80 illustrated in FIG. 7 may beused to engage an inner housing 92 of a dose setting mechanism, such asthe dose setting mechanism illustrated in FIGS. 5 and 6. As illustrated,the inner housing 92 comprises a first and a second flexible lockingelements 98 a, 98 b located near a distal end 93 of the inner housing92. Also near this distal end 93 is a circular shaped housing portion94. This housing portion 94 defines a cavity portion 101 having an innersurface and along this inner surface there are two internally radiallydirected recesses 96 a and 96 b.

During assembly, the coupling part 80 will be positioned to slide intothe cavity 101 of the housing portion 94 such that the second set ofprotruding members 86 a, 86 b of the coupling part 80 slide throughrecesses 96 a, 96 b of the housing portion 94, respectively. The secondmembers 86 a, 86 b will then be positioned to reside over an externalsurface of the inner housing flexible elements 98 a, 98 b, respectively.In this position, the drug delivery device will not be primed but ratherthe dose dial sleeve 103 will be locked out and prevented from rotating.As such, a user of such a drug delivery device will be prevented fromselecting a dose, that is, the user will be prevented from rotating thedose dial sleeve 103 before the user has under taken a drug deliverydevice priming step.

FIG. 9 illustrates the coupling part 80 engaged with the distal end 93of the inner housing 92. As illustrated, the coupling part 80 is in aninitial position or in a non-primed state, before device priming occurs.In this initial position, the set of protruding elements 86 a, 86 breside over the surface of the flexible elements 96 a, and 96 b,respectively. Therefore, when a cartridge holder is connected to thehousing and is rotated (as illustrated in FIGS. 4 and 5), the couplingpart 80 also rotates. As the coupling part 80 is rotated in thedirection of arrow D1, the first set of protruding elements 86 a, 86 brotate over the flexible locking elements 98 a, 98 b and end upreleasing these flexible locking elements, and therefore stop faces 106a, 106 b from the dose dial sleeve. FIG. 10 illustrates the couplingpart 80 and inner housing 92 after rotating the coupling part to releasethe flexible locking elements and thereby completing of the primingstep. As illustrated, the coupling part 80 has been rotated to a finalor stop position 102 and the coupling part 80 has now been is rotatedless than 360 degrees so as to push the inner housing flexible elements98 a, 98 b radially inward. This releases the inner housingstop faces106 a, 106 b, from the dose dial sleeve 103. FIG. 11 illustrates a closeup view of the stop faces 106 a, 106 b provided along the distal end ofthe inner housing 92. The dose dial sleeve 103 is also illustrated witha scale arrangement 104 provided along an outer surface of this dosedial sleeve 103. The dose dial sleeve 103 has mating stop faces 97 a, 97b that engage with stop faces 96 a, 96 b on the inner housing

A spindle nut 114 is coupled to the coupling part 80 so that when thecoupling part 80 rotates the spindle nut 114 rotates to drive a spindle124 distally. As illustrated, this spindle nut 114 is circular in shapeand comprises a first and a second helical ramp 116 a, 116 b. Thespindle nut 114 further comprises a circular cavity having a male groovemember 118. Once assembled, the spindle nut 114 is rotationally coupledto the coupling part 80 so that when a cartridge holder is coupled to adose setting member and the cartridge holder is rotated, the spindle nut114 rotates along with the cartridge holder. The first and secondhelical ramps 116 a, 116 b serve to drive the spindle nut 114 in adistal direction (i.e., towards the injection site) when the cartridgeholder is rotated. Where the spindle nut 114 is used in drug deliverydevice comprising a non-resettable drug delivery device, these helicalramps lock the cartridge holder rotationally at the end of the primingstep. However, where the spindle nut is used in a resettable drugdelivery device, the helical ramps are detented so as to allow thecartridge housing 72 to be rotated back and removed to enable a newcartridge to be fitted.

The height of the helical ramps 116 a, 116 b help to offset any slack inthe drive mechanism that drives the spindle of the dose settingmechanism forwards to dispense a dose. In this manner, rotating thecartridge holder is generally equivalent to pressing on a dose button ofthe dose setting mechanism so as to take up slack in the drivemechanism.

FIG. 13 illustrates the spindle nut 114 coupled to the coupling part 80and inner housing 92 of a dose setting mechanism. In this illustration,the coupling part 80 is rotated by the cartridge holder (notillustrated). This in turn rotates the spindle nut 114. As illustrated,this spindle has at least two overlapping grooves. Preferably, one ofthese grooves 130 is engaged with a portion of the drug deliver deviceand could be either helical or axially extending along its length.

Because in one arrangement the spindle 124 is threaded to a portion ofthe drug delivery device, as the spindle nut 114 rotates, it advancesthe spindle 124 axially in the distal direction D2 128 so as to primethe drug delivery device. The rotation of the cartridge housing, asmentioned, also unlocks the dose dial sleeve 103 to allow a user to nowsett a first dose of medication for the drug delivery device.

Exemplary embodiments of the present invention have been described.Those skilled in the art will understand, however, that changes andmodifications may be made to these embodiments without departing fromthe true scope and spirit of the present invention, which is defined bythe claims.

1. A drug delivery device, said drug delivery device comprising: a dosesetting mechanism comprising a spindle; and a cartridge holder coupledto said dose setting mechanism, said cartridge holder comprising acartridge having a movable bung at one end of said cartridge; whereinsaid cartridge holder must be rotated before a dose may be set with saiddose setting mechanism.
 2. The invention of claim 1 wherein saidcartridge holder must be rotated with respect to said dose settingmechanism before said dose may be set with said dose setting mechanism.3. The invention of claim 1 wherein rotation of said cartridge holderprimes said drug delivery device.
 4. The invention of claim 1 whereinrotation of said cartridge holder moves said spindle into an abuttingengagement with said bung of said cartridge.
 5. The invention of claim 1wherein rotation of said cartridge holder enables a dose dial sleeve ofsaid dose setting mechanism to rotate.
 6. The invention of claim 5wherein rotation of said dose dial sleeve allows a user of said dosesetting mechanism to set said dose.
 7. The invention of claim 1 whereinafter said cartridge holder is rotated, said cartridge holder isrotationally locked to said dose setting mechanism.
 8. The invention ofclaim 7 wherein after said cartridge holder is rotated, said cartridgeholder is rotationally locked to said dose setting mechanism by way of aone way, non-return detent feature.
 9. The invention of claim 1 whereinsaid cartridge holder provides a visual indication that said cartridgeholder must be rotated before said dose may be set by said dose settingmechanism.
 10. The invention of claim 1 wherein said drug deliverydevice is a resettable drug delivery device.
 11. The invention of claim1 wherein said drug delivery device is not a resettable drug deliverydevice.
 12. The invention of claim 1 wherein said cartridge holder mustbe rotated less than 360 degrees before a dose may be set with said dosesetting mechanism.
 13. A priming mechanism for a drug delivery device,said priming mechanism comprising: a dose setting mechanism comprising aspindle; and a dose dial sleeve; a cartridge holder, said cartridgeholder comprising a cartridge, said cartridge comprising a movable bungnear a proximal end of said cartridge; a coupling part connecting saidcartridge holder to said dose dial sleeve of said dose settingmechanism, and a spindle nut rotationally coupled to said coupling part,said spindle nut coupling said cartridge holder to said spindle of saiddose setting mechanism; such that when said cartridge holder is rotatedwith respect to said dose setting mechanism, said spindle nut is rotatedand moves said spindle into an abutting engagement with said bung. 14.The invention of claim 13 wherein said coupling part unlocks said dosedial sleeve so that said dose dial sleeve may be rotated to set a dose.15. The invention of claim 13 wherein said coupling part comprises athin metal pressing.
 16. The invention of claim 13 wherein said couplingpart comprises a rigid coupling component (Ok).
 17. The invention ofclaim 13 wherein said dose setting mechanism comprises at least oneflexible locking element, wherein when said cartridge holder is rotated,said coupling part also rotates to thereby release said flexible lockingelement and allowing said dose dial sleeve to rotate and allow a user ofsaid medical delivery device to set a dose.
 18. The invention of claim13 wherein said spindle nut further comprises a plurality of helicalramps, said plurality of helical ramps driving said spindle nut in adistal direction when said cartridge holder is rotated so that saidspindle abuts a first surface of said bung.